All these ingredients have unique functions. For instance, butyl acetate, isopropyl alcohol and ethyl acetate are solvents which dissolve the polymers ethylene and nitrocellulose. Plasticizers such as the polyvinyl butyral, trimethylpentanediyl dibenzoate, polyethylene terephthalate, acetyl tributyl citrate, and epoxy resin help to achieve a durable, firm finish. Silica has the role of spreading the pigments as well as preventing settling of the polish. Benzophenone-1 is a sunscreen agent while stearalkonium bentonite is a suspending agent. The rest of the ingredients are various pigments and colorants that are used in the diverse range of Opi nail polish. Starting in 2006, Opi has been producing updated nail products to appeal to the female market who want non-toxic nail treatments. The reformulated nail products lack any trace of toluene, dibutyl phthalate, or formaldehyde.